Fuel-feeding system for furnaces



July 2, y1929. w, A, EDWARDS 1,719,397l

FUEL FEDING 'SYSTEM FOR FURNAGES v Filed Deo. '7, 1923 Mwd/MM.

@wlw Patented July 2, 1929.

UNITED STATES WILLIAM A. EDVUARDS, OF CHICAGO, ILLINOIS.

FUEL-FEEDING SYSTEM FOR FURNACES.

Application filed December The purpose of this invention is to provide an improved system of supplying vaporiz-` able fuel to a furnace. It consists in the elements and features of construction shown and described as indicated in the claims.

In the drawings i Figure l is a partly sectional side elevation of a furnace equipped with this .invention, the furnace wall being broken out through the fire box for disclosing the fuel supply connections theretoand a detail sec tion being made axial with respect to the fuel mixture discharge int-o the fire chamber of the furnace.

Figure 2 is a vertical section through the steam generating chamber, axial with respect to the pipe connections.

Figure 3 is a section axial with respect to the fuel mixture conduit at the point of delivery of the liquid fuel thereinto for the mixture. i

The drawings show a furnace in conventional form without intention to show or limit the invention to any particular construction of a furnace beyond the relation of the fuel feeding system thereto. The wall of the fire box or tire chamber is indicated at A, a water or air chamber for air or water to be heated for tirculation in the heating system served by the furnace is indicated conventionally at B. N o grate or other support for fuel in combustion is indicated,

none being required in view of the fact that the fuel is vaporous or gaseous. A low level source of liquid fuel is indicated in two forms, one consisting of the fuel tank, C, which may be at any desired level but which delivers the fuel by gravity to a level-gow erning chamber or float bowl shown conventionally at C1. This level governing cham` ber is designedly at a definitely lower level than the tire chamber of the furnace regardless of the level at which the supply tank, C, may be positioned for supplying the float bowl, C?, by gravity; and it has a fuel delivery connection from its lower part discharging into the fuel mixture conduit as hereinafter explained substantially at the governed level of the float bowl indicated by the dotted line, c1. An alternatively position-ed fuel source is shown at C which indicates conventionally a supply tank at a position lower than the fuel connection therefrom to the fuel mixture conduit hereinafter described.

In the fire chamber exposed to the flame thereof there is positioned a steam generat- 7, 1923.` Serial No. 679,275.

ing chamber, D, having awater supply con nection, Dl, controlled bythe valve, D2, for permitting the delivery of water, drop by drop, or in the limited quantity into :1nd onto the heated bottoni of the generating chamber, D, for developing steam and `producing pressure at that point in the chamber. F rom the upper part. of the steam generating chamber, D, a steam conduit, E, leads outward and then downward to a return bend, El, from which the conduit returns upward and as shown at F and is then extended inward into the fire chamber looped back outward and reflexed at F 2 for discharge at the constriction of a venturi-lil e inlet to the fire chamber shown at G. Inn mediately above the return bend, lill, 'the conduit comprising` a venturi-like constricted portion, f, at the constrictiou'of which the liquid fuel conduit, c2, from the low level fuel source discharges, producing in the conduit, F, beyond t-he venturi a fuel mixture, vaporous in character, forwhich reason the said conduit, referred to as the steam conduit at the portion between the generating chamber, D, and the vent-uri, f, is referred to as the fuel mixture conduit, beyond said venturi, j.

For initially heating the steam generating chamber, D, for flame hasbeen produced in the lire chamber, there is provided a tray or pan, H, positioned under the steam generator in which a small amount of liquid fuel may be placed and ignited for initial develw opment of steam in the generator which later is heated for generation of `steam by the flame produced in the fire chamber.

From the foregoing descrpition `it will be understood that steam is generated and pressure produced in D, which in its discharge through the venturi, f, draws in the liquid fuel from either of the low level `sources indicated.` If both are present the liquid fuel `conduits from them leading to the venturi, f, will be provided 'with valves as indicated at c2 and o3, one or the other of which will be closed according to which source is to be utilized for the time being. The fuel mixture resulting` beyond the venturi, j, being vaporous in character in the sense that the liquid fuel which is not volatilized by the steam at this stage is carried in suspension in minute globules. This vaporous fuel mixture being delivered through the portion of the conduit which extends within the fire chamber box is thoroughly vaporized and may be substantially converted into a fixed gas by the time it is discharged at the constriction of the venturi, G; and it is here discharged at comparatively high velocity causing a large addition of air to be drawn in with it through the air inlet opening, g, of said venturi, G, the mixture being rendered completely combustible and explosive, that is, containing the necessary quantity of air to support quick and complete combustion of the combustible elements furnished by the liquid fuel.

Suitable valves and chambers may be interposed in the fuel conduit and in the steam conduit and at the air inlet port of the venturi, G, whereby the operator. may control the quantity of fuel and thereby the intensity of the fire, and also to regulate the proportions of the mixture of air and combustible fuel so as to render the combustion perfect whether the fire desired is up to the capacity of the furnace or only a fraction of that capacity, provided always the heat must lbe sufficient to maintain the generation of steam in the generator', D.

It will be understood that the capacity of the chamber, D, should be such with relation to the area againstwhich the water is delivered drop by drop for generating steam, that the pressure resulting intermittently as drops of water are thus delivered, may serve to maintain an approximately uniform pressure in the chamber' for like approximately `uniform discharge of fuel mixture, and not discharge by flashes, as would be the case if the chamber, D; were small relatively to the volume of steam generated from each drop of water delivered.

l. In a fuel feeding system for furnaces in combination with a furnace box, a source of liquid fuel at a lower level than the tire box; a steam conduit leading from the upper part of said device exteriorly of the furnace downward to a level approximating that of the fuel source and returning upward outside the furnace, ysaid conduit terminating for discharge inwardly with respect to the tire box and comprising at a low point in said exterior course a flow-accelerating constriction beyond which it is extended into the fire box and reflexed out therefrom for terminating for discharge back inwardly with respect to the lire box; a conduit from the fuel source and terminating for fuel f discharge within said steam conduit proximate to said constriction thereof; whereby the steam current in the conduit outside the furnace is exposed to cooling before contact with the fuel and the steam conduit subscqulent to the constriction becomes a fuel mixture conduit; and a relatively large and constricted air inlet passage lalding from the ire box in the lower part thereof within which said fuel mixture conduit discharges; whereby the steam and fuel vapor mixture is exposed in the lire box prior to the tinal air admixture therewith at the tinal discharge back into the tire box.

2. In a fuel feeding system for furnaces, in combination with a furnace lire box, a source of liquid fuel at a lower level than the fire box; a steam generating device mounted in the tire box consisting of a metal member having an extended surface arca cxposcd to heating means. and heating means` therefor; a connection for delivering water drop-by-drop onto said heated area, whereby steam is generated without accumulation of a body of water exposed to the healing means; a steam conduit leading from the upper part of said device exterierly of the furnate downward to a level approximating that of the fuel source and returning upward outside thc furnace; said conduit terminating for discharge inwardly with respect to the lire box and comprising at a low point in said exterior course a tlow-accelcrating constriction; a conduit from the fuel source terminating for Vfuel discharge within said stem conduitproximate to said constriction thereof, whereby the steam current in the conduit outside the furnace is exposed to cooling before contact with the fuel, and said steam conduit subsequent to the coustriction, becomes a fuel mixture conduit; and a relatively large air inlet passage having a flow-accelerating constriction, said passage leadng into the lire box at the lower part thereof', within which said fuel mixture conduit discharges.

In testimony whereof, l have hereunto set my hand at Chicago, illinois, this 5th day of December, 1923.

lVILLIAM A. EDWARDS. 

